Electrically-heated cooker.



A. J. KERCHER. ELECTRICALLY HEATED COOKER. APPLICATION FILED Dac. I4. |912.

- Patented Ailg. 24,1915.

wITNEssEs 1 'y INvENToR @du @LW AR'THUI JdimcHEJf/f I M v ms ATToRNEYs ABTHUBVJ. kan/CHER, or BERKELEY, GALIFORNIA, assidu-on 'ro BERKELEY ELECTRIG- GOOKEIR. COMPANY, OF BERKELEY, CALIFORNIA A ,CORPORATION OF CALIFORNIA.

E'LnccrIcALLY-Hm'rnn cooks-R'.

Specification o f Letters Patent.

Patented Aug. e4, 1915.

y Application led December 1 4, 1912. Serial No. 736,830. r

T0 alZ whom-t may concern.'

Be itknown that I, a citizen'of the .United States, and a resident of Berkeley, county of Alameda, and State which the' heat is transferred to the substance to bevcooked, and the regulating and controlling means is arranged to be.oper atedby the change in pressure within the ARTHUR J. KERCHER,

ture. At a given temperature a certain pressure is' reached and -the controlling mechanism 1s arranged to openvthe circuit when such temperature is exceeded, and to point. In devices of this nature'it is-not advisable to produce averyhigh pressure and the diaphragmis varranged to operate with an increase of a few pounds above atmos- -of California, have invented certain new close the circuit when the temperature drops et and useful Improvements in Electricallybelow this point. By this meansthe sub- I-Ieated Cookers, of which the following is a stance to be cooked is subjected to a subspecification. stantially constant temperature and is 4 The invention relates to cookers which cooked to better advantage than in instances are adapted to be heated to the proper temwhere the temperature varies in any sub- 65 perature by means of an electric current, `stantial degree. and more particularly to cookers in which rPhe cooker consists of a receptacle 2 havthe substance or substances to be cooked and ing double side walls 3-'-4 and double botthe heating units are entirely inclosed by a tc'm walls 5-6 spaced apart to form a chamheat insulating material so that all of the ber .7 therebetween, Theijoint between the 70 heat generated by the heating element -is side walls 3 4 at their upper ends is preferutilized in cooking the substance. ably formed by alloying or fusing the two The bject of the invention is to provide walls together. a cooker in which theheat is transferred to A quantity of Water or other liquid is all parts 'of the eXte'ror of the cooking vesplaced in the chamber 7 so that it completely 75 selyby steam'. x covers the'bottom thereof and the chamber is Another object of the invention is to prothem sealed, the pressure therein being sub-v vide a duble walled receptacle surrounding Stantially atmospheric pressure. the cooking receptacle with means for re- The heating unitsI 12 'of any desired conducing the pressure therein as it is increased struction are arranged on the bottom 6 of 80 due to an Aincrease in temperature. the receptacle 2, and arel insulated therefrom Afurther object of the invention is to proby a thin strip of suitable insulating and vide an electrically heated cooker in which heat resisting material such as mica. the electric current is controlledto maintainl Below the receptacle 2 is a quick throw a substantially'cnstant temperature within switch 13 which is operated by a buckling B5 the cooker. n diaphragm arranged in the casing 14 which The device possesses other advantageous occurs-within the chamber 7. P The upper features, which, with the foregoing, will be face of the diaphragm is exposed to the set forth at length in the following descrippressure within the chamber 7 and the lower tion1whereI shall outline in full that form face is exposed to atmospheric, pressure. 90 of the` invention which I have selected for An increase in pressure in the chamber to a illustration .in the drawing accompanying certain-point causes the diaphragm to spring and forming part of the present description. downwardand open the switch, and a low- The novelty of the invention will be inering of the temperature below such point eluded in the claims succeeding said descripallows the diaphragm to spring back, allow- 95 tion. From this it will be apparent that I ing the switch to close. do not limit myself to the showing made The closed receptacle and the heafting by such drawing and description, as I may units are surrounded .by a casing 15 of heat adopt many variations within the scope of insulating material which 'is preferably iumy invention as expressed in said'claims. closed in asheet metal case 16. 1o!

The figure is a vertical section of the Itis evident that. if the chamber 7, which cooker showing the improvements of my .p contains air and water, were heated, the

. invention. i p pressure therein, due tothe' expansion of the rlIhe heating element is adapted to heat a air, would increase to quite ahigh degree body of liquid'. in a closed receptacle from before the temperature reached thecooking 10d 55 receptacle, caused by a. change4 in temperaphere, and when such pressureis reached the 11 I ductor 19 connecting the chambers 7 and 17 extends. The conductor 19 is connected to the chamber 7 adjacent the upper portion thereof so that substantially all of the eX- panded air may pass into chamber 17. /A ball valve 21, vprovided with means for preventing its displacement, controls the enftrance of the pipe 19 into the chamber 17,

so that there may not be any rapid circulation of the air back to the chamber' 7.

The casing 18 is preferably arranged in contact with the sheet metal casing 16, so that the heat of the-'air therein is rapidly radiated, thereby reducing the pressure in the chamber 17, andthe size of the chamber 17 is such that the air from chamber 7 can be forced thereinto vwithout objectionably increasing the pressure therein. In the drawing the size of chamber 7 is exaggerated in proportion to the size of chamber 17. When the current has been shut off and vthe temperature and pressure in chamber 7 is lowered, the air from chamber 17 will gradually leak past the ball valve 21 until the pressures in the two chambers are again in equilibrium.

By the use of this invention an efficient and even transference of the heat from the heating units to all parts of the cooking vessel is obtained and a cooking temperature is obtained without the production of any objectionably high pressures.

I claim:

1. In a cooker, a double-walled receptacle adapted to contain the food to be cooked,

the chamber between the walls being closed and being partly filled with liquid which vaporizes and permeates the chamber when heated, a closed casing spaced from said receptacle and a conduit connecting the fined Wah iiquid,

chamber with the casing through which thc air from the chamber passes into the casing when the receptacle is heated.

2. In a cooker, a closed receptacle adapted to contain a quantity of liquid, a closed expansion chamber arranged above the level of the liquid and spaced'from said receptacle, a conduit connecting said receptacle and chamber and a valve in said conduit.

3. In a cooker, a closed receptacle adapted to contain a quantity of liquid and air, a closed casing spaced from said receptacle, a conduit connecting said receptacle above the level of the liquidv therein with said casing through which air passes from the receptacle to the casing when the receptacle is heated, and a check valvein said conduit.

4. In a cooker, a double walled receptacle adapted to contain the food to be cooked, the chamber between the walls being closed and containing air and a small amount of liquid,

which liquid is adapted to be vaporized by the application of heat, a casing of heat insulating material surrounding said receptacle, a closed casing arranged in thermal contact with the atmosphere and a conductor connecting said casing vwith said receptacle through which the air in said receptacle passes to the casing when the receptacle is heated. v

5. In a cooker,

a casing of heat insulating material surrounding said receptacle, a closed expansion chamber in thermal communication with the atmosphere, a conduit connecting said closed chamber and recep- Itacle, and a valve in said conduit.

6. In a cooker, a heat insulated closed receptacle partly filled with water and adapt` ved to surround the `food to be cooked, and

an expansion lchamber arranged to radiate its heat into the atmosphere, spaced apart from said receptacle, but in communication therewith.

` In testimony whereof, I have hereunto set my hand at Berkeley, California, this 6th day of VDecember 1912.

ARTHUR J. KERCHER.

In presence of` L. D. VATERMAN, M. D. SNELL.

soV

a closed receptacle partly 

